JP2006022340A - Polyester resin - Google Patents

Abstract

[PROBLEMS] To achieve molding without reducing the transparency even if the molding temperature is lower than that of the conventional molding, so that generation of acetaldehyde during molding and mold contamination during molding are suppressed, and molding with excellent transparency is also achieved. It is possible to obtain a body, and particularly to provide a polyester resin suitable for forming a bottle for food and drink.
A dicarboxylic acid component having terephthalic acid or an ester-forming derivative thereof as a main component and a diol component having ethylene glycol as a main component are produced by polycondensation through an esterification reaction or a transesterification reaction. Polyester resin, wherein the haze of a molded article injection-molded at 270 ° C. is 50% or less at a thickness of 5 mm.
[Selection] Figure 1

Description

  Since the present invention can be molded without deteriorating the transparency even when the molding temperature is lower than that of the prior art, generation of acetaldehyde during molding and mold contamination during molding are suppressed, and the transparency is also excellent. The present invention relates to a polyester resin which can obtain a molded body and is particularly suitable for molding bottles for food and drinks.

  Conventionally, polyester resins such as polyethylene terephthalate resins are excellent in mechanical strength, chemical stability, gas barrier properties, hygiene, etc., and are relatively inexpensive and lightweight. These bottles are widely used. For example, these bottles are manufactured by injection molding a bottomed tubular preform, reheating and softening the preform, and then stretch-blow molding.

  However, as these bottles for food and drink, etc., polyester resins using polycondensation catalysts of general-purpose antimony compounds and germanium compounds are mainly used, but at the time of melt molding such as injection molding of preforms By-products such as acetaldehyde and cyclic low-polymer form in the resin, and the acetaldehyde adversely affects the flavor of the contents of the bottle, and the cyclic low-body contaminates the blow mold. There has been a problem that productivity is greatly reduced for cleaning the mold.

  On the other hand, in order to reduce the generation of by-products at the time of melt molding in a polyester resin using the latter germanium compound as a polycondensation catalyst, for example, Japanese Patent Publication No. 7-37515 discloses a resin after polycondensation. Is disclosed in which the catalyst in the resin is deactivated by bringing it into contact with hot water of 50 to 100 ° C. However, although this method can improve mold contamination, the problem of reducing productivity is unavoidable.

On the other hand, it is easily recalled that the generation of these by-products can be suppressed by lowering the molding temperature at the time of injection molding than the conventional one, but conventionally known antimony compounds and germanium compounds are used as polycondensation catalysts. In the case of the polyester resin, although the generation of by-products during molding can be suppressed by lowering the molding temperature, the resulting molded product is whitened, resulting in a problem that the transparency is greatly reduced. Many polyester resins using a compound as a polycondensation catalyst have also been proposed, but this conventionally known resin has a yellowish color tone and generates by-products such as acetaldehyde and cyclic low-polymer during molding. Remarkably, even if the molding temperature is lower than before, the generation of these by-products cannot be sufficiently suppressed, and the resulting molded product is whitened and the transparency is greatly reduced. There is a problem in that.
Japanese Patent Publication No. 7-37515

  The present invention has been made in view of the above-described prior art, and can be molded without losing transparency even if the molding temperature is lower than that of the prior art. Therefore, generation of acetaldehyde during molding, and mold contamination during molding It is an object of the present invention to provide a polyester resin suitable for molding bottles for foods and drinks, etc.

  The present invention is produced by polycondensing a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol through an esterification reaction or a transesterification reaction. And a polyester resin having a haze of 50% or less at a thickness of 5 mm.

  According to the present invention, even if the molding temperature is lower than before, molding is possible without impairing transparency, so that generation of acetaldehyde during molding and mold contamination during molding are suppressed, and transparency is also achieved. An excellent molded product can be obtained, and particularly a polyester resin suitable for molding a bottle for food or drink can be provided.

  The polyester resin of the present invention is obtained by polycondensing a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol through an esterification reaction or a transesterification reaction. A dicarboxylic acid component in which terephthalic acid or an ester-forming derivative thereof occupies 90 mol% or more, further 95 mol% or more, particularly 99 mol% or more of the dicarboxylic acid component, and ethylene glycol is a diol. It is preferably produced by polycondensation with a diol component occupying 90 mol% or more, further 95 mol% or more, particularly 97 mol% or more of the component. If the proportion of terephthalic acid or its ester-forming derivative in the dicarboxylic acid component and the proportion of ethylene glycol in the diol component is less than the above ranges, oriented crystallization of molecular chains due to stretching when molding into a bottle or the like becomes insufficient. In addition, mechanical strength, gas barrier properties, heat resistance and the like as molded articles such as bottles tend to be insufficient.

  Examples of the ester-forming derivative of terephthalic acid include alkyl esters having about 1 to 4 carbon atoms and halides. Examples of dicarboxylic acid components other than terephthalic acid or ester-forming derivatives thereof include, for example, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalic acid, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4 , 4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and other aromatics Alicyclic dicarboxylic acids such as dicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, and succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid Aliphatic dicarbo such as acid Acid, as well as the alkyl esters having about 1 to 4 carbon atoms, and halides, one or two or more like may also be used as a copolymerization component.

  Examples of the diol component other than ethylene glycol include diethylene glycol by-produced in the reaction system, and the proportion of the diethylene glycol in the diol component is 3 mol% or less including the amount added from outside the system as a copolymer component. It is preferable that it is 1.5 to 2.5 mol%. Other diol components include, for example, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1,3- Aliphatic diols such as propanediol, polyethylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, 2,5 -Cycloaliphatic diols such as norbornane dimethylol, xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, 2,2-bis (4'- -Hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, aromatic diols such as bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and 2,2-bis (4′-hydroxyphenyl) propane One or two or more of ethylene oxide adduct or propylene oxide adduct may be used as a copolymerization component.

  Further, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, heneicosanol, octacosanol, benzyl alcohol, stearic acid, behenic acid, benzoic acid Monofunctional components such as acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, sugar ester One or two or more multifunctional components such as trifunctional or more may be used as the copolymerization component.

  In the polyester resin of the present invention, it is essential that the haze of a molded article injection-molded at 270 ° C. is 50% or less at a thickness of 5 mm, and this haze is preferably 30% or less, preferably 20% or less. Is more preferable and 10% or less is particularly preferable. If the haze exceeds the above range, the transparency when molded into a bottle or the like at a low temperature is inferior, and it must be molded at a high temperature, so that the generation of acetaldehyde and mold contamination during molding are sufficient. It cannot be suppressed.

Further, the polyester resin of the present invention has a resin acetaldehyde content (AA _S ; ppm) in a molded article after injection molding at 270 ° C. and an acetaldehyde content (AA ₀ ; ppm) of the resin before injection molding. The difference (AA _S -AA ₀ ) is preferably 15 ppm or less, more preferably 13 ppm or less, and particularly preferably 10 ppm or less. If the value of (AA _S -AA ₀ ) exceeds the above range, problems such as the loss of the flavor of the content food or drink tend to occur when it is used as a molded article such as a bottle in a food or drink container.

In addition, the polyester resin of the present invention has a cyclic trimer content (CT _S ; wt%) of the resin in the molded product after injection molding at 270 ° C. and a cyclic trimer content of the resin before injection molding ( CT _0; the difference between the weight%) (CT _S -CT ₀₎ is preferably at 0.05 wt% or less, more preferably at 0.03 wt% or less, is 0.01 wt% or less Is particularly preferred. If the value of (CT _S −CT ₀ ) exceeds the above range, mold contamination tends to occur when a bottle or the like is molded.

The polyester resin of the present invention preferably has an acetaldehyde content (AA ₀ ) of 5 ppm or less, and more preferably 3 ppm or less. When the acetaldehyde content (AA ₀ ) exceeds the above range, there is a tendency that problems such as impairing the flavor of the content food or drink are likely to occur when used as a molded article such as a bottle in a food or drink container. Further, the cyclic trimer content (CT ₀ ) is preferably 0.50% by weight or less, and more preferably 0.40% by weight or less. If the cyclic trimer content (CT ₀ ) exceeds the above range, mold contamination tends to occur during the molding of bottles and the like. The intrinsic viscosity ([η]) is preferably 0.70 to 0.90 dl / g as a value measured at 30 ° C. with a mixed solvent solution of phenol / tetrachloroethane (weight ratio 1/1). 0.70 to 0.80 dl / g is more preferable. If the intrinsic viscosity ([η]) is less than the above range, mechanical strength as a molded article such as a bottle tends to be insufficient. On the other hand, if it exceeds the above range, generation of by-products tends to increase during the molding of the bottle or the like. It becomes. As the color tone, the color coordinate b value of Hunter's color difference formula in the Lab color system described in Reference 1 of JIS Z8730 is preferably 4 or less, and more preferably -5 to 2. When the b value exceeds the above range, the color tone of a molded body such as a bottle tends to be yellowish.

In the present invention, the haze as a molded body at 270 ° C., the acetaldehyde content (AA _S ), the cyclic trimer content (CT _S ), and the acetaldehyde content (AA ₀ ) as a resin. ), Cyclic trimer content (CT ₀ ), intrinsic viscosity ([η]), color coordinate b value and the like are within the above ranges, the polycondensation of the polyester resin is carried out in the presence of a titanium compound. Accordingly, the polyester resin of the present invention preferably contains the titanium compound.

  Specific examples of the titanium compound include tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, and tetra-t-butyl. Titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, titanium acetate, titanium oxalate, potassium potassium oxalate, sodium titanium oxalate, potassium titanate, sodium titanate, titanium titanate-aluminum hydroxide mixture, titanium chloride, titanium chloride Aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, ammonium hexafluorotitanate, titanium acetylacetonate, etc. , Tetra -n- propyl titanate, tetra -i- propyl titanate, tetra -n- butyl titanate, titanium oxalate, titanium oxalate potassium are preferred.

  Polycondensation is a coexistence of phosphorus compounds in terms of polycondensation, haze as a molded product, reduction of by-products such as acetaldehyde and cyclic trimer, and color tone of the resulting resin. Accordingly, the polyester resin of the present invention preferably contains the phosphorus compound.

  Here, specific examples of the phosphorus compound include orthophosphoric acid, polyphosphoric acid, and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, Trivalent (triethylene glycol) phosphate, ethyl diethylphosphonoacetate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, etc. Phosphorus compound, phosphorous acid, hypophosphorous acid, and diethyl phosphite, trisdodecyl phosphite, trisnonyl decyl phosphite, And trivalent phosphorus compounds such as rephenyl phosphite. Among them, orthophosphoric acid, tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate, phosphorous acid are preferable. , Tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate are particularly preferred.

  In addition, polycondensation is carried out in terms of the polycondensation property, haze as a molded product, reduction of by-products such as acetaldehyde and cyclic trimer, and the color tone of the resulting resin. It is preferably polycondensed in the presence of at least one compound selected from the group consisting of compounds of group IIA and group IIA metal elements. Accordingly, the polyester resin of the present invention contains the metal element. It is preferable that the compound of this is contained.

  Here, the compound of the metal elements of Group IA and Group IIA of the periodic table is a diol such as ethylene glycol or a compound soluble in water, for example, lithium, sodium, potassium, magnesium, calcium. Oxides, hydroxides, alkoxides, acetates, carbonates, oxalates, halides, etc., such as lithium acetate, sodium acetate, potassium acetate, magnesium oxide, magnesium hydroxide, magnesium Examples thereof include alkoxide, magnesium acetate, magnesium carbonate, calcium oxide, calcium hydroxide, calcium acetate, and calcium carbonate. Of these, magnesium compounds are particularly preferred.

  In the present invention, the amount used in the polycondensation of the compound of the titanium compound, the phosphorus compound, and the metal element of Group IA and Group IIA of the periodic table, and the content in the polyester resin associated therewith, It is preferably 0.002 to 1 mol, more preferably 0.002 to 0.5 mol, and more preferably 0.002 to 0.2 mol as titanium atom (Ti) per ton of polyester resin. Is particularly preferred. The phosphorus atom (P) is preferably 0.02 to 4 mol, more preferably 0.02 to 2 mol, and atoms of metal elements of Group IA and Group IIA of the periodic table. The total (M) is preferably 0.04 to 5 mol, more preferably 0.04 to 3 mol.

  In addition, the amount of each of the titanium compound, the phosphorus compound, and the compound of the metal element of Group IA and Group IIA of the periodic table includes titanium atom (Ti), phosphorus atom (P), and period. As the sum (M) of atoms of the metal elements of Group IA and Group IIA in the table, the molar ratio of the phosphorus atom (P) to the titanium atom (Ti) [P / Ti ] Is 1 or more, further 5 or more, particularly 15 or more, and the molar ratio of the sum (M) of atoms of the metal elements of Group IA and Group IIA of the periodic table to titanium atom (Ti) [M / Ti] is 2.5 to 250, more preferably 15 to 150, particularly 25 to 50, and the total of atoms of metal elements of Group IA and Group IIA of the periodic table (M) The molar ratio [P / M] of the phosphorus atom (P) with respect to 0 is more than 0 to 1, more preferably 0.2 to 1. In addition, the molar ratio of phosphorus atom (P) to the sum of titanium atom (Ti) and the sum (M) of atoms of Group IA and IIA metal elements in the periodic table [P / (Ti + M)] Is preferably 0.2 to 1, and more preferably 0.4 to 1.

  Resin obtained when the molar ratio [P / Ti] and the molar ratio [P / (Ti + M)] are less than the above range, and the molar ratio [M / Ti] exceeds the above range. On the other hand, the molar ratio [P / M] and the molar ratio [P / (Ti + M)] exceed the range, and the molar ratio [M / Ti ] Is less than the above range, the polycondensability tends to decrease.

  In the present invention, polycondensation is performed in the presence of the titanium compound, or further in the presence of the phosphorus compound, or further, a compound of a metal element of Group IA and Group IIA of the periodic table, In this case, the polyester resin of the present invention may contain the germanium compound. In view of transparency of the obtained resin, the content thereof is preferably 0.4 mol or less, more preferably 0.3 mol or less as germanium atoms (Ge) per ton of polyester resin. More preferred is 0.25 mol or less.

  Specific examples of the germanium compound include germanium dioxide, germanium tetroxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, germanium tetra-n-butoxide, and the like. Germanium is preferred.

  In the present invention, during polycondensation, a metal compound other than the above-mentioned compounds may be present within a range not impairing the effects of the present invention, and accordingly, the polyester resin of the present invention contains the metal compound. May be. As the metal compound in that case, aluminum, chromium, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, silver, tin, antimony, lanthanum, cerium, hafnium, tungsten, gold and other oxides, hydroxides, Examples include alkoxides, carbonates, phosphates, carboxylates, halides and the like. In addition, it is preferable that said each compound and said other compounds are soluble in alcohol, such as ethylene glycol, and water.

The polyester resin of the present invention preferably undergoes an esterification reaction or a transesterification reaction between a dicarboxylic acid component mainly composed of the terephthalic acid or its ester-forming derivative and a diol component mainly composed of ethylene glycol. Although it is produced by polycondensation in the presence of a titanium compound, it is basically based on a conventional production method for polyester resins. That is, a dicarboxylic acid component mainly composed of the terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol are usually at a temperature of about 240 to 280 ° C., usually 0 to 0 in an esterification reaction tank. The esterification reaction product obtained after the esterification reaction under agitation under a pressure of about 4 × 10 ⁵ Pa for about 1 to 10 hours or the ester exchange reaction in the presence of a transesterification catalyst or The polyester low molecular weight product as the transesterification reaction product is transferred to a polycondensation tank, and in the presence of the compound, usually at a temperature of about 250 to 290 ° C., gradually from normal pressure to gradually reduced to 1133 to 13.3 Pa. It is made by melt polycondensation for about 1 to 20 hours under stirring under a reduced pressure of about, and these are made in a continuous manner or a batch manner.

  At that time, the esterification rate of the low molecular weight polyester as the esterification reaction product or transesterification reaction product (the ratio of the esterification by reacting with the diol component out of the total carboxyl groups of the raw dicarboxylic acid component) is 95% or more is preferable. In the case of transesterification, since it is generally necessary to use a transesterification catalyst, the transparency of the resin generally obtained tends to be inferior. Therefore, in the present invention, it is produced through an esterification reaction. preferable.

  In addition, during the polycondensation, addition to the reaction system such as the titanium compound, the phosphorus compound, the compound of the metal elements of Group IA and IIA of the periodic table, or the germanium compound is ethylene glycol, etc. It is preferably carried out as a solution of alcohol, water, etc., and the timing of addition of terephthalic acid or its ester-forming derivative, ethylene glycol, and other dicarboxylic acid components and diol components used as necessary It may be any stage of the slurry preparation process, esterification reaction or transesterification process, or the initial stage of the melt polycondensation process. Periodic table group IA and group IIA metal element compound, or the germanium compound, then the titanium Preferably one made in the order of compound.

  As a specific addition step of each compound, particularly in a continuous production method, the phosphorus compound is added in a slurry preparation step, and the compounds of the metal elements of Group IA and Group IIA of the periodic table, or the germanium compound In addition, it is preferable that the titanium compound is added after the esterification reaction or transesterification reaction step, the compound of the metal elements of the Group IA and IIA of the periodic table, or the germanium compound is an ester. The titanium compound is added to the polycondensation tank or the transfer pipe to the polycondensation tank of the low molecular weight polyester as the esterification reaction product or the transesterification reaction product. It is particularly preferred.

  Also, usually, the resin obtained by melt polycondensation is extracted in a strand form from an extraction port provided at the bottom of the polycondensation tank, and is cooled with water or after water cooling, and then cut with a cutter to form pellets, chips, etc. In addition, the granule after the melt polycondensation is usually in an inert gas atmosphere such as nitrogen, carbon dioxide, argon, etc., in a steam atmosphere, or in a steam-containing inert gas atmosphere. In general, after the surface of the resin granule is crystallized by heating at a temperature of about 60 to 180 ° C., the resin is usually adhered in an inert gas atmosphere or / and under a reduced pressure of about 1333 to 13.3 Pa. It is preferable that the solid phase polycondensation is carried out by heat treatment usually for about 50 hours or less while flowing so that the granules do not stick together at a temperature just below 80 ° C. Further with capable of high polymerization degree, it is also possible to reduce the acetaldehyde and cyclic trimer of the reaction by-products.

  Furthermore, the resin obtained by melt polycondensation or solid phase polycondensation as described above is used for the purpose of improving thermal stability and reducing by-products such as acetaldehyde and cyclic trimer during molding. Usually, a treatment such as a water treatment for immersing in warm water of 40 ° C. or higher for 10 minutes or more, or a steam treatment for contacting water vapor of 60 ° C. or higher or a steam-containing gas for 30 minutes or more may be performed.

  In addition, the polyester resin of the present invention is used after the injection molding at 270 ° C. in order to express a sufficient crystallization rate in heating the stopper portion at the time of molding of a bottle or the like and crystallizing it by imparting heat resistance. The temperature rising crystallization temperature (Tc) of the resin in the molded body is preferably 180 ° C. or less, more preferably 155 to 165 ° C., and particularly preferably 157 to 164 ° C. Here, the temperature rise crystallization temperature (Tc) was raised from 20 ° C. to 285 ° C. at a rate of 20 ° C./min using a differential scanning calorimeter and melted at 285 ° C. for 3 minutes. After maintaining the state, it is rapidly cooled with liquid nitrogen, again heated from 20 ° C. to 285 ° C. at a rate of 20 ° C./min, and the crystallization peak temperature observed in the middle is measured.

  And in the polyester resin of this invention, in order to adjust the temperature rising crystallization temperature (Tc) of the resin in the molded article after the injection molding at 270 ° C. to the above range, a crystalline thermoplastic different from the polyester resin is used. The resin is preferably contained in a content of 0.0001 to 1000 ppm, preferably 0.0005 to 100 ppm, more preferably 0.001 to 10 ppm. As the crystalline thermoplastic resin, typically, a polyolefin resin is used. And polyamide resin.

  Examples of the polyolefin resin include homopolymers of α-olefins having about 2 to 8 carbon atoms such as ethylene, propylene, and butene-1, those α-olefins, ethylene, propylene, 1-butene, and 3-methyl. -1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and other α-olefins having about 2 to 20 carbon atoms, vinyl acetate, acrylic acid, Examples thereof include copolymers with vinyl compounds such as methacrylic acid, acrylic acid esters, methacrylic acid esters, vinyl chloride, and styrene. Specifically, for example, low, medium and high density polyethylene (branched or linear) Ethylene homopolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, Len-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer Such as ethylene resins, propylene homopolymers, propylene-ethylene copolymers, propylene-ethylene-1-butene copolymers, and the like, and 1-butene homopolymers, 1-butene-ethylene copolymers Examples thereof include 1-butene-based resins such as coalescence and 1-butene-propylene copolymer.

  Examples of the polyamide resin include polymers of lactams such as butyrolactam, δ-valerolactam, ε-caprolactam, enantolactam, ω-lauryllactam, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-amino. Polymers of amino acids such as octanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 1,4-butanediamine, 1,5-pentanediamine, 1,5-hexanediamine, 1, Aliphatic diamines such as 6-hexanediamine, 1,9-nonanediamine, 1,11-undecadiamine, 1,12-dodecanediamine, α, ω-diaminopolypropylene glycol, 1,3- or 1,4-bis ( Cycloaliphatic diamines such as aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane) , Diamines such as aromatic diamines such as m- or p-xylylenediamine, and aliphatic dicarboxylic acids such as glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and cycloaliphatic dicarboxylic acids Examples thereof include polycondensates with dicarboxylic acids such as aromatic dicarboxylic acids such as dicarboxylic acid, terephthalic acid, and isophthalic acid, or copolymers thereof. Specific examples include nylon 4, nylon 6, nylon 7 and the like. , Nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6/66, nylon 6/610, nylon 6 / 12, nylon 6 / 6T, nylon 6I / 6T, and the like.

  In order to make the polyester resin contain the crystalline thermoplastic resin in the present invention, a method in which the crystalline thermoplastic resin is directly added to the polyester resin and melt-kneaded so that the content falls within the range, Alternatively, in addition to a conventional method such as a method of adding and melting and kneading as a master batch, the crystalline thermoplastic resin is melted at the production stage of the polyester resin, for example, during melt polycondensation (raw material, slurry, catalyst, etc.) Immediately after polycondensation, immediately after pre-crystallization, at the time of solid-phase polycondensation, immediately after solid-phase polycondensation, etc. A liquid such as water that is added directly or dispersed as a granular material is brought into contact with a polyester resin chip-like material, or a gas such as air mixed as a granular material and a polyester resin chip. Or contacting the Jo body, or, after being mixed by a method such as to be in contact with the member of the crystalline thermoplastic resin to flow under the conditions of the polyester resin chips like body can also be by a method in which melt kneading. Among the latter methods, chips after melt polycondensation of the polyester resin, during pneumatic transportation to the pre-crystallization machine, during pneumatic transportation to the solid phase polycondensation tank, or after solid phase polycondensation A method in which a crystalline thermoplastic resin is mixed in the air for pneumatic transportation at the time of pneumatic transportation to the storage tank or pneumatic transportation to the molding machine is preferable.

  In the present invention, the polyester resin includes an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, an antiblocking agent, an antifogging agent, a nucleating agent, a plasticizer, a colorant, a filler, and the like. It may be contained.

  The polyester resin of the present invention is formed into a bottle or the like by, for example, forming it into a preform by injection molding and then performing stretch blow molding or by blow molding a parison formed by extrusion molding. After being formed into a sheet by extrusion molding, it is formed into a tray or container by thermoforming, or the sheet is biaxially stretched into a film or the like, which is particularly useful in the food and beverage packaging field. . Among them, it is suitable for forming a bottle by a blow molding method in which a preform obtained by injection molding is biaxially stretched. For example, liquid seasonings such as carbonated beverages, alcoholic beverages, soy sauce, sauces, mirin, and dressings Furthermore, it is suitably used as a container that requires heat resistance, such as a fruit juice drink, a drink such as tea or mineral water, etc.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
Esterification in which a slurry of 43 kg (260 mol) of terephthalic acid and 19 kg (312 mol) of ethylene glycol was previously charged with about 60 kg of bis (hydroxyethyl) terephthalate and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa. The reaction vessel was sequentially supplied over 4 hours, and after the completion of the supply, an esterification reaction was further carried out over 1 hour, and about half of the esterification reaction product was transferred to the polycondensation vessel.

Subsequently, ethyl acid phosphate, magnesium acetate, and tetra-n-butoxytitanium, each in the form of an ethylene glycol solution, are supplied to the polycondensation tank to which the esterification reaction product has been transferred. The phosphorus atom (P) was added at 0.85 mol, the magnesium atom (M) was 4.031 mol, and the titanium atom (Ti) was 0.021 mol. While raising the temperature from 250 ° C. to 280 ° C. over 2 hours and 30 minutes and reducing the pressure from normal pressure to 4 × 10 ² Pa in 1 hour and maintaining the same pressure, the intrinsic viscosity of the obtained resin is 0.55 dl / When the melt polycondensation is performed for a period of time g, the strand is extracted from the extraction port provided at the bottom of the polycondensation tank, cooled in water, and then cut into chips. Accordingly, to produce a polyethylene terephthalate resin of about 50 kg.

  Subsequently, the polyester resin chip obtained above was crystallized by continuously feeding it into a stirring crystallizer maintained at about 160 ° C. so that the residence time was about 5 minutes, and an inert oven (ESPEC) (IPHH-201 model)), dried at 160 ° C. for 2 hours under a nitrogen stream of 40 liters / minute, and then heated at 210 ° C. for a time such that the intrinsic viscosity becomes 0.745 dl / g. Condensed.

The obtained polyester resin chips, by the following method, the content of the copolymer component, the metal atom content in the metallic compound, acetaldehyde content (AA _0), the cyclic trimer content (CT _0), unique The viscosity ([η]) and the color coordinate b value as the color tone were measured, and the results are shown in Table 1.

Content of copolymerization component A solution obtained by dissolving a resin sample in a mixed solvent of deuterated chloroform / hexafluoroisopropanol (weight ratio 7/3) so as to have a concentration of 3% by weight is used for a nuclear magnetic resonance apparatus (JEOL Ltd.) ¹ H-NMR was measured by using “JNM-EX270 type” manufactured by the manufacturer, and each peak was assigned. The content of the copolymerization component was measured from the integrated value of the peak, and the mol% was calculated.

A plasma emission spectrophotometer (JOBIN YVON) was prepared for a resin sample containing 2.5 g of a metal atom content , which was ashed with hydrogen peroxide in the presence of sulfuric acid and completely decomposed and then made up to 50 ml with distilled water. ICP-AES “JY46P type”) was used, and the amount was converted to the molar amount in 1 ton of polyester resin.

Acetaldehyde content (AA ₀ )
A resin sample (5.0 g) is precisely weighed, sealed in a 50 ml internal volume cylinder with 10 ml of pure water under a nitrogen seal, and heated and extracted at 160 ° C. for 2 hours. The amount of acetaldehyde in the extract is determined by isobutyl alcohol. Was quantified using gas chromatography (“GC-14A” manufactured by Shimadzu Corporation) as an internal standard.

Cyclic trimer content (CT ₀ )
4.0 mg of a resin sample is precisely weighed and dissolved in 2 ml of a mixed solvent of chloroform / hexafluoroisopropanol (volume ratio 3/2), further diluted by adding 20 ml of chloroform, and reprecipitated by adding 10 ml of methanol. Then, the filtrate obtained by filtration was evaporated to dryness, the residue was dissolved in 25 ml of dimethylformamide, and the amount of cyclic trimer (cyclotriethylene terephthalate) in the solution was measured by liquid chromatography (“LC-” manufactured by Shimadzu Corporation). 10A ").

Intrinsic viscosity ([η])
After 0.25 g of the freeze-pulverized resin sample was dissolved in a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1) at a concentration (c) of 1.0 g / dl at 110 ° C. for 20 minutes, Ubbelohde Using a type capillary viscometer, the relative viscosity (η _rel ) with the solvent was measured at 30 ° C., and the specific viscosity (η _sp ) and concentration (c) determined from this relative viscosity (η _rel ) −1 determine the specific (η _sp / c), also determine the concentration (c) a 0.5g / dl, 0.2g / dl, the respective ratios even with when a _{0.1g / dl (η sp / c} ), From these values, the ratio (η _sp / c) when the concentration (c) was extrapolated to 0 was determined as the intrinsic viscosity [η] (dl / g).

A color resin sample is filled in a cylindrical powder color measurement cell having an inner diameter of 36 mm and a depth of 15 mm by grinding, and using a color measurement color difference meter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.), JIS Z8730. The color coordinate b value of Hunter's color difference formula in the Lab color system described in Reference 1 was obtained as a simple average value of values measured at four locations by rotating the measurement cell 90 degrees by the reflection method.

Subsequently, the obtained resin was dried at 160 ° C. for 16 hours or more in a vacuum dryer (“DP-41 type” manufactured by Yamato Kagaku Co., Ltd.), and then an injection molding machine (“M-” manufactured by Meiki Seisakusho Co., Ltd.). 70AII-DM ”), cylinder temperature 270 ° C., back pressure 5 × 10 ⁵ Pa, injection rate 40 cc / sec, holding pressure 35 × 10 ⁵ Pa, mold temperature 25 ° C., molding cycle about 75 seconds, FIG. A stepped molded plate having a thickness of 50 mm, a width of 100 mm, and a thickness of 6 steps from 6 mm to 3.5 mm in the horizontal direction and having a step difference of 0.5 mm was injection molded. In FIG. 1, G is a gate portion.

The obtained molded plate was measured for haze, acetaldehyde content (AA _S ), and cyclic trimer content (CT _S ) by the method shown below, and the results are shown in Table 1.

About the thickness 5.0mm part (C part in FIG. 1) in a haze shaping | molding board, it measured using the haze meter ("NDH-300A" by Nippon Denshoku).

Acetaldehyde content (AA _S )
Measurement was performed in the same manner as described above using a sample cut into a 4 mm square from the rear end portion (B portion in FIG. 1) of the 3.5 mm thick portion of the molded plate.

Cyclic trimer content (CT _S )
Measurement was performed in the same manner as described above using a sample cut out from a tip portion (A portion in FIG. 1) having a thickness of 3.5 mm on the molded plate.

Separately, the obtained polyester resin chip was dried at 130 ° C. for 10 hours in a vacuum dryer, and then the cylinder temperature was 270 ° C. and the back pressure was 5 with an injection molding machine (“FE-80S” manufactured by Nissei Plastic Industries) × 10 ⁵ Pa, injection rate 45 cc / second, holding pressure 30 × 10 ⁵ Pa, mold temperature 20 ° C., molding cycle about 40 seconds, outer diameter 29.0 mm, height 165 mm, average wall thickness 3.7 mm, weight A 60 g test tubular preform (preform) was injection molded.

The obtained preform was visually observed for transparency and evaluated according to the following criteria. The results are shown in Table 1.
A: Transparency is very good.
○: Excellent transparency.
X: Whitening and poor transparency.

Subsequently, the obtained preform was heated in a near-infrared irradiation furnace equipped with a quartz heater for 70 seconds, left at room temperature for 25 seconds, charged into a blow mold set at 160 ° C., and stretched. While stretching in the height direction with a rod, blow molding at 7 × 10 ⁵ Pa for 1 second, further blow molding at 30 × 10 ⁵ Pa for 40 seconds, heat setting, air cooling, outer diameter about 95mm, height about 500 bottles of 305 mm, average body thickness of about 0.37 mm, weight of about 60 g, and internal volume of about 1.5 liters were molded, and then the acetaldehyde odor was determined for the 501st to 503th bottles by the following method. The surface appearance of the bottle body was visually observed and evaluated according to the following criteria to evaluate the mold contamination, and the results are shown in Table 1.

The acetaldehyde odor bottle was sealed with a cap and allowed to stand in an oven set at 50 ° C. for 1 hour, then removed, and the acetaldehyde odor inside the bottle was subjected to a sensory test and evaluated according to the following criteria.
A: Almost no acetaldehyde odor.
○: Less acetaldehyde odor.
X: Strong acetaldehyde odor.

Mold contamination ◎: Surface smooth and no mold contamination.
○: The surface smoothness is slightly inferior, and therefore the mold contamination is slightly inferior, but there is no practical problem.
X: The surface becomes rough and rough, and the adhesion of foreign matter is recognized, and the mold contamination is poor.

Examples 2-3
The same procedure as in Example 1 was conducted except that the addition amounts of magnesium acetate and tetra-n-butoxytitanium during melt polycondensation were changed as shown in Table 1, and the results are shown in Table 1.

Examples 4-8
At the time of melt polycondensation, ethyl acid phosphate, magnesium acetate, germanium dioxide, and tetra-n-butoxytitanium were each added as an ethylene glycol solution sequentially at intervals of 5 minutes, and the respective addition amounts are shown in Table 1. Except for this change, the same procedure as in Example 1 was performed, and the results are shown in Table 1.

Example 9
The solid phase polycondensation polyester resin obtained in Example 5 was further treated in the same manner as in Example 5 except that it was immersed in hot water at 90 ° C. for 4 hours for water treatment. The results are shown in Table 1. .

Example 10
Using the polyester resin obtained in Example 5, low-density polyethylene was added at the time of injection molding of the stepped molded plate and at the time of injection molding of the preformed body, and the temperature rising crystallization of the resin on the stepped molded plate was performed. The temperature (Tc) is measured by the following method, and the plug portion of the obtained preform is heated for 180 seconds by a quartz heater type plug portion crystallizer, and then a mold pin is inserted to plug the plug portion. The results were shown in Table 1, except that the shape and dimensions of the plug portion were visually observed and evaluated according to the following criteria.

Temperature rising crystallization temperature (Tc)
After cutting out a tip part (A part in FIG. 1) having a thickness of 3.5 mm in the molded plate and drying it at 40 ° C. for 3 days with a vacuum dryer, using a sample cut out from the non-surface part, about 10 mg was precisely weighed and sealed using an aluminum open pan and pan cover (normal pressure type, “P / N SSC000E030” and “P / N SSC000E032” manufactured by Seiko Denshi), and a differential scanning calorimeter (manufactured by Seiko) Using “DSC220C”), the temperature was increased from 20 ° C. to 285 ° C. at a rate of 20 ° C./min under a nitrogen stream, and the molten state was maintained at 285 ° C. for 3 minutes. The temperature was raised from 0 ° C. to 285 ° C. at a rate of 20 ° C./min, and the crystallization peak temperature observed along the way was measured.

Mouth part shape, size ◎; is very stable dimensional accuracy is obtained.
○: Stable dimensional accuracy is obtained.
X: Crystallization is insufficient, and the shape is cramped.

Comparative Example 1
At the time of melt polycondensation, ethyl acid phosphate, magnesium acetate, and antimony trioxide were each added as an ethylene glycol solution sequentially at intervals of 5 minutes, and the addition amounts were as shown in Table 1. Was carried out in the same manner as in Example 1, and the results are shown in Table 1. The injection-molded preform was whitened and it was impossible to obtain a practical bottle, so the bottle was not molded.

Comparative Example 2
Example 1 except that orthophosphoric acid and germanium dioxide were each added as ethylene glycol solutions sequentially at intervals of 5 minutes during melt polycondensation, and the amounts added were as shown in Table 1. The results are shown in Table 1. The injection-molded preform was whitened and it was impossible to obtain a practical bottle, so the bottle was not molded.

Comparative Example 3
Except that the amount of germanium dioxide added was changed and that the obtained solid phase polycondensation polyester resin was further immersed in hot water at 90 ° C. for 4 hours for water treatment, the same as in Comparative Example 2. The results are shown in Table 1. The injection-molded preform was whitened and it was impossible to obtain a practical bottle, so the bottle was not molded.

Comparative Example 4
At the time of melt polycondensation, tetra-n-butoxytitanium, magnesium acetate, and ethyl acid phosphate were each added as ethylene glycol solutions sequentially at 5-minute intervals, and the respective addition amounts were as shown in Table 1. Except this, it was carried out in the same manner as in Example 1, and the results are shown in Table 1. The injection-molded preform was whitened and it was impossible to obtain a practical bottle, so the bottle was not molded.

Reference example 1
The same procedure as in Comparative Example 2 was performed except that the polyester resin obtained in Comparative Example 2 was used and the cylinder temperature at the time of injection molding of the stepped molding plate and the injection molding of the preform was set to 280 ° C. The results are shown in Table 1.

(A) of the step-shaped formation board for physical property evaluation shape | molded in the Example is a top view, (b) is a front view.

Claims (8)

  A polyester resin produced by polycondensing a dicarboxylic acid component having terephthalic acid or its ester-forming derivative as a main component and a diol component having ethylene glycol as a main component through an esterification reaction or a transesterification reaction. A polyester resin characterized in that a haze of a molded article injection-molded at 270 ° C. is 50% or less at a thickness of 5 mm. The difference (AA _S −AA ₀ ) between the acetaldehyde content (AA _S ; ppm) of the resin in the molded article after injection molding at 270 ° C. and the acetaldehyde content (AA ₀ ; ppm) of the resin before injection molding is The polyester resin according to claim 1, which is 15 ppm or less. Difference between cyclic trimer content (CT _S ; wt%) of resin in molded product after injection molding at 270 ° C. and cyclic trimer content (CT ₀ ; wt%) of resin before injection molding The polyester resin according to claim 1 or 2, wherein (CT _S -CT ₀ ) is 0.05% by weight or less. The resin before injection molding is acetaldehyde content (AA ₀ ) 5 ppm or less, cyclic trimer content (CT ₀ ) 0.50 wt% or less, intrinsic viscosity ([η]) 0.70 to 0.90 dl / g The polyester resin according to any one of claims 1 to 3, which has a color coordinate b value of 4 or less in Hunter's color difference formula.   The polycondensation is performed in the presence of a titanium compound, and the content of the titanium compound is 0.002 to 1 mole of titanium atom (Ti) per ton of polyester resin. The polyester resin as described in.   The polycondensation is carried out in the presence of a phosphorus compound, and the content of the phosphorus compound is 0.02 to 4 mol as a phosphorus atom (P) per ton of a polyester resin, and a titanium atom (Ti) The polyester resin according to claim 5, wherein a molar ratio [P / Ti] to 1 is 1 or more.   It is polycondensed in the coexistence of at least one compound selected from the group consisting of compounds of group IA and group IIA metal elements of the periodic table, and the content of the metal element compound is polyester The total number of atoms (M) per ton of resin is 0.04 to 5 mol, and the molar ratio [M / Ti] to titanium atoms (Ti) is 2.5 to 250, and the total number of atoms (M ) The molar ratio [P / M] of the phosphorus atom (P) to 0 exceeds 1, and the molar ratio of the phosphorus atom (P) to the sum of the titanium atom (Ti) and the sum of the atoms (M) [P / ( The polyester resin according to claim 6, wherein Ti + M)] is 0.2-1.   The polyester resin according to any one of claims 1 to 7, wherein 99 mol% or more of the dicarboxylic acid component is terephthalic acid or an ester-forming derivative thereof, and 97 mol% or more of the diol component is ethylene glycol.

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